A total of 1,586 Norwegian nurses answered the Bergen Shift Work Sleep Questionnaire. Those who “often” or “always” experienced insomnia and sleepiness problems were categorised as having shift-related sleep problems.

The responses were analysed to uncover the links between various sleep problems and different shifts (day, evening and night shifts as well as days off) and steady as well as rotating shifts.

The study was conducted by researchers at the Norwegian Competence Centre for Sleep Disorders at the University of Bergen (at Haukeland University Hospital) and the Swedish Karolinska Institutet.

Different shifts caused different problems

The results show that sleep disorders vary depending on different work shift regimes. Sleeping problems related to night shifts are more prevalent among those who work a rotating three-shift schedule. These are nurses who at various times work days, evenings and nights instead of solely working steady night shifts.

Nearly 68 percent of the first group and 42 percent of the latter were plagued by sleep problems.

At the same time upwards of 11 percent of the steady night shift workers experienced sleeping problems on their days off. Among those who rotated between two or three shifts, 4.2 percent and 3.6 percent respectively suffered sleep problems on days away from work.

Evening shift insomnia was more prevalent in the two-shift rotation schedule than the three-shift rotation schedule (just shy of 30 percent and 20 percent respectively).

Start with a day shift

The findings confirm earlier studies showing that the negative effects of shift work hinge on the types of shifts worked and how they are rotated.

Generally it is recommended that two-shift or three-shift schedules start with a diurnal rhythm, beginning with a day shift, then an evening shift and then, when applicable, a night shift as the third watch.

Other measures for reducing sleep disorders can be to schedule as few night shifts in a row as possible and follow the same day-night rhythms as long as possible before changing to another rotation. This helps keep the body’s day-night rhythm from being thrown off too much in relation to actual days and nights.

Three-shift routines and steady night shifts are worst.

The study concludes that shift-related sleep problems differ depending on the different work schedules, with the most problems related to three-shift rotations and steady night shifts.

“However, sleep problems were present in all shifts and schedules. This suggests that both shifts and work schedules should be considered in the study of shift work-related sleep problems,” conclude the researchers.